1. Field of the Invention
The present invention relates to a positioning device, particularly to a changeable positioning device for dental drilling.
2. Description of the Prior Arts
Teeth are calcified structure formed in the mouth for biting and chewing. An adult's teeth may be damaged by oral diseases or external forces, and the broken teeth are unable to regenerate. After the teeth are damaged, the alveolar bone and the gums of the mouth may be shrunk, and this may impair the eating capability. To avoid the above-mentioned problem, the common treatment is dental implant to replace the broken or lost teeth with denture.
When a patient's tooth is broken or missing, a common treatment is to replace the tooth with a denture. A common method of a denture implant is fixed tooth implant. The fixed tooth implant is processed by first drilling a socket at an appropriate position where a tooth is missing on an alveolar bone in a patient's mouth, and then an artificial implant fixture is implanted into the socket. The socket is sutured after implantation of the artificial implant fixture. When the artificial implant fixture grows fully integrated with the alveolar bone, an abutment having a screw is mounted on the artificial implant fixture. The denture is mounted on the abutment and fully sustained on the alveolar bone by the abutment and the artificial implant fixture, so the denture can bear the biting force thus to restore the biting function of the patient's teeth.
Taiwan patent number M498344, which is incorporated herein as a reference as shown in FIG. 8, discloses a drilling positioning auxiliary device for tooth implantations comprising a positioning device 90 formed in a hollow semi-cylinder. The positioning device 90 is embedded in a surgical guide in order to facilitate a drill's drilling in the alveolar bone. The positioning device 90 comprises a base body 91 and at least one guide portion 92 abutting the base body 91, and increases or decreases the number of the at least one guide portion 92 to adjust the size of the socket drilled. Although the semi-cylinder design allows the drill to be easily placed into the positioning device 90 in the limited oral space, the design also increases the instability of drilling, and the drill may be displaced due to lack of a supporting wall. Besides, the at least one guide portion 92 does not tightly connect with the base body 91 when the drill is drilling toward the axial direction of the base body 91 and the at least one guide portion 92 is synchronously moved with the drill, thereby causing great disturbance during operation.
Therefore, to develop stable drilling for the drill and stably combining the guide body and the positioning device, the disadvantages in the prior arts should be resolved.